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Topic: Ground Hum Discovery with Pot Volume Pedal |
Jon Light (deceased)
From:
Saugerties, NY
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Posted 30 Nov 2012 11:33 am |
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This will not surprise anyone who knows about this stuff but I stumbled across it today and thought I'd share.
I changed a pot on a Goodrich 120 and before closing it up I tried it out to make sure everything was as I wanted it. It was. But there was some hum.
I plugged in another pedal for comparison and it was silent. I checked for stray wires, bad joints, bad cables, bad plugs, continuity of all the grounds and the chassis....everything was good. Plugged it back in, it hummed. I laid it on its back and it was quiet.
Conclusion? Sitting on the floor (bare wood) without its bottom plate and rubber feet, not good. Fully assembled? Quiet. Good.
Didn't shatter any earths but it was a good illustration of simple physical stuff that can have an impact and it was a good lesson/reminder for me.
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Jerry Overstreet
From:
Louisville Ky
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Posted 30 Nov 2012 12:09 pm
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I came upon this phenomenon a few years ago playing outdoors on grass. I was using an open chassis pedal bar mount Derby, like the Emmons. It was humming like a transformer. Slipping a sheet of cardboard under it shut it up.
I subsequently built a mini plate covered with shielding tape to cover the electronics. No further issues. Made a few for my buds as well. |
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Jon Light (deceased)
From:
Saugerties, NY
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Posted 30 Nov 2012 12:18 pm
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| You know, Jerry---I got lazy and did not spend the time isolating the few variables here. Was my solution the putting of the plate back on (shielding), the putting of the rubber feet back on (insulating) or the putting of the feet back on (elevating the chassis a bit off of the floor (ground)? I should run tests of each factor to test this. Some day. :>) |
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John Swain
From:
Winchester, Va
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Posted 30 Nov 2012 2:31 pm
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| Jerry, I had the same problem with an Emmons VP on grass..I put plastic bag under it and that killed the hum!..JS |
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Lee Baucum
From:
McAllen, Texas (Extreme South) The Final Frontier
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Posted 30 Nov 2012 2:51 pm
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| Jon - The same thing happened to me the first time I changed out a pot in a pedal. |
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